ÿþ t " ( a , + ") a > 0
"
f ( t , x ) µ ( d x ) ,
"t
A
"
1
A : = ( 1 , + ") , f ( t , x ) = e x p ( - t x ) , µ : = l .
x
2
1 - e - a x
g ( a ) = l ( d x ) ; a e" 1 .
x 2
( 0 , ")
"
“( ±) = x ±- 1 e - x l ( d x ) , ± > 0 .
0
“ ( ±)
f : R ’! R g : R ’! R
f " g ,
[ f " g ] ( t ) : = f ( t - s ) g ( s ) d s ,
R
[ f " g ] ( k ) = f ( k ) " g .
"
( a k ) k "Z | n | k a n <